Many different terms are used for the devices that run our small computing projects. In addition there are lots of different hardware/software platforms. Many are pin compatible, similar in size and function and can achieve the same result in different ways.
Here are some of the common terms:
A microcontroller is a small computer built into a single chip. This chip contains the processor, RAM, EPROM and I/O pins. These generally are designed for executing I/O and small computational functions.
The Arduino is not just a microcontroller. It’s a platform that includes a microcontroller. Usually an ATMega chip. An Arduino also includes other chips and components to make it easy to communicate with, program and prototype with.
Embedded systems are also small computers all on one chip (also called SoC for System On a Chip). These are generally more powerful (32 bit as opposed to 8 or 16 bit CPUs on microcontrollers) than a microcontroller and can run full operating systems like Linux or Windows. They too have other chips for communication and I/O and offer programming in higher level languages supported by the operating system. The Raspberry Pi is considered an embedded system but also falls under the next classification. Embedded Systems are also found in many consumer electronics like MP3 players and cell phones. In these cases they aren’t for prototyping or user programming but their features are very similar. iPhone and Android phones/tablets also use SoCs extensively.
Single Board Computer
A single board computer is an Embedded System with ALL the bells and whistles on a small board. This usually includes USB, Ethernet, Video, GPIO, Storage and possibly expandable memory. The Raspberry Pi is definitely a single board computer. It also has prototyping components like most microcontroller platforms. It’s a powerful fully featured system.